Add setting to disable all AI features (#34896)

https://github.com/user-attachments/assets/674bba41-40ac-4a98-99e4-0b47f9097b6a


Release Notes:

- Added setting to disable all AI features

crates/client/src/client.rs

@@ -151,6 +151,7 @@ impl Settings for ProxySettings {
 
 pub fn init_settings(cx: &mut App) {
     TelemetrySettings::register(cx);
+    DisableAiSettings::register(cx);
     ClientSettings::register(cx);
     ProxySettings::register(cx);
 }
@@ -548,6 +549,33 @@ impl settings::Settings for TelemetrySettings {
     }
 }
 
+/// Whether to disable all AI features in Zed.
+///
+/// Default: false
+#[derive(Copy, Clone, Debug)]
+pub struct DisableAiSettings {
+    pub disable_ai: bool,
+}
+
+impl settings::Settings for DisableAiSettings {
+    const KEY: Option<&'static str> = Some("disable_ai");
+
+    type FileContent = Option<bool>;
+
+    fn load(sources: SettingsSources<Self::FileContent>, _: &mut App) -> Result<Self> {
+        Ok(Self {
+            disable_ai: sources
+                .user
+                .or(sources.server)
+                .copied()
+                .flatten()
+                .unwrap_or(sources.default.ok_or_else(Self::missing_default)?),
+        })
+    }
+
+    fn import_from_vscode(_vscode: &settings::VsCodeSettings, _current: &mut Self::FileContent) {}
+}
+
 impl Client {
     pub fn new(
         clock: Arc<dyn SystemClock>,